Some conventional display units for conference or the like comprise a coordinates inputting function such as a digitizer or a touch panel which enables coordinates data to be input to a personal computer connected to the display unit. The display unit can also be used as a pointing device to input, to the personal computer, coordinates data on a position on a screen which is designated by a user using a pen or a finger. This enables a cursor displayed on the display unit to be moved to a designated position on the screen of the display unit. Further, by operating switches, corresponding to mouse buttons, provided on the pen, or touching the screen, it is possible to input button operation information to the personal computer.
Some display units comprise a plurality of video input terminals, any of which can be selected using buttons or the like so that video signals to be displayed on the screen can be input through the selected terminal. Other display units comprise a picture-in-picture function and/or a picture-out-picture function that enable a plurality of the video input terminals to be simultaneously selected using buttons or the like so as to provide simultaneous display of video signals from the selected video input terminals on the screen. The picture-in picture-function displays sub-screens in a main screen. The picture-out-picture function instead reduces the size of the main screen and displays sub-screens in free spaces outside the main screen.
A display unit has also been proposed in which video outputs from different personal computers (PCs) can be connected to a plurality of the video input terminals of the display unit and displayed in multi-windows, each corresponding to a respective PC, using the picture-in picture-function or picture-out-picture function. With some of these display units, when a position on the screen is designated using a pen or the finger, a positional signal is sent to the personal computer that is outputting a video displayed at the designated position so that the screen displayed by the personal computer (PC) can be operated by the display unit (see Japanese Patent Application Laid-Open No. 2003-22177).
A display unit comprises a coordinates inputting function such as a digitizer or a touch panel which enables a plurality of areas to be simultaneously operated. With this function, different personal computers (PCs) can be connected to the respective video input terminals of the display unit, and the display unit displays videos corresponding to the various PCs, using the picture-in-picture function or picture-out-picture function. Each of the PCs can then be operated by designating the main screen or the sub-screen of the display unit using the pen or finger.
A window control method has also been proposed which is applied to, for example, an operation system composed of a multi-window system. In this method, in a case where windows are displayed so as to overlap, a particular window is made transparent so as to enable inputs to another particular (hidden) window and its operations to the window (see Japanese Patent Application Laid-Open No. 11-249782).
A problem with the former Japanese Patent Application Laid-Open No. 2003-22177 is that if windows overlap, inputs cannot be given to an area of an underlying hidden window. A problem with the window control method in the latter Japanese Patent Application Laid-Open No. 11-249782 is that if the overlying window is made transparent to enable inputs to the underlying hidden window, inputs cannot be given to the transparent window. Further, even if inputs can be simultaneously given to a plurality of positions of a window, inputs can be given only to the underlying window (nontransparent window) if a plurality of windows overlap.